There exists many types of local area networks (LAN) which are in use, or are under developement, or in the process of being standardized. Generally, in a LAN, there exists a bus and a plurality of stations (or nodes) attached to the bus. Each station (or node) attached to the bus has the same status as any other station, i.e., there is no master and slave relationship between the stations. Thus, no features of an LAN are known to exist whereby a predetermined station can interrogate any other station and further where an interrogation/replay between stations results in a diagnostic and recovery type function.
The present invention allows a node (or remote node) on a local area network to be diagnosed and manipulated from a predetermined node that has an operator interface (or has an interface which permits I/O, or interaction with an entity (i.e., an operator) outside the local area network). The predetermined node (denoted herein as a supervisor node) having the operator interface can therefore control/diagnose/receive status reports of any of the remote nodes. An interface apparatus is provided at each node of the local area network which permits communication to the predetermined node (or supervisor node) independent of the remote node host microprocessor.